1. Field of the Invention
This invention relates to an apparatus for treating flue gases such that the feed flue gas is mixed with ammonia and irradiated with electron beams to be freed of nitrogen oxides and/or sulfur oxides.
2. Prior Art
Conventionally, the diffusion and mixing of ammonia in a flue gas has been improved either by injecting ammonia at a position upstream of or near the inlet to the reactor so that it will stay within the flue gas for a prolonged time or by using a punching metal for mixing with the gas.
It is generally held that denitration and desulfurization reactions proceed almost simultaneously and the low efficiency of denitration has primarily been ascribed to insufficient mixing and diffusion of ammonia and this is why nobody has ever thought of adding ammonia at a position closer to the region of irradiation with electron beams.
With the recent enforcement of more rigorous regulations in respect to the concentration of leak ammonia in flue gases, it has been necessary to control the leak ammonia. In fact, however, ammonia has been supplied in excessive amounts in the prior art in order to ensure that denitration and desulfurization reactions proceed in the desired direction. But then the excessive addition of ammonia causes an increased amount of ammonia to remain in the flue gas. Since the current regulations on the emission of flue gases requires that not only NO.sub.x, SO.sub.x and dust but also leak ammonia be controlled on the emission, it has been necessary for the ammonia to be injected at an optimal position in the necessary minimum amount which ensures the desired efficiency of denitration and desulfurization reactions.